聚酯/TGIC粉末涂料固化动力学分析

Curing Kinetics Analysis of Polyester/TGIC Powder Coatings

通过傅里叶变换红外光谱(FT-IR)分析EWA1113与PWA1221两种聚酯/TGIC粉末涂料固化前后结构的变化,判断粉末涂料是否发生固化反应;运用差示扫描量热分析(DSC)分析粉末涂料的固化过程,探究不同颜料对粉末涂料的固化行为的影响。结果表明:EWA1113与PWA1221两种粉末涂料的理论固化温度范围分别为133. 2~232. 2℃和151. 6~232. 2℃;采用T-β外推法确定EWA1113粉末的固化工艺参数,线性拟合可得到凝胶化温度T0为97℃,固化温度Tp为159. 6℃,后处理温度Tf为195. 98℃;通过Kissinger微分法和Doyle-Ozawa方程研究反应的活化能,通过计算分析得出活化能Ea为92. 14 kJ/mol;采用Crane经验方程进行计算得出固化反应级数n为0. 93;并通过DSC分析涂层的固化特性、固化度与温度的关系、理论最小固化时间等,得出在同一温度下,升温速率越慢,粉末涂料的固化程度越大的结论。

In this paper,an analysis of structures before and after curing of EWA1113 and PWA1221 polyester/TGIC powder coatings by Fourier transform infrared spectroscopy(FT-IR)were described. The results confirmed a curing reaction for the powder coatings. The differential scanning calorimetry(DSC) test was conducted to study the curing process of powder coatings. The effects of different pigments on the curing behavior of powder coatings were investigated. The theoretical curing temperature of EWA1113 and PWA1221 powder coatings were 133. 2~232. 2 ℃ and 151. 6~232. 2 ℃ respectively. The curing process parameters of EWA1113 powder were determined by T-β extrapolation method,indicating the gelling temperature T097 ℃,the curing temperature Tp159. 6 ℃,and the post-treatment temperature Tf195. 98 ℃. The activation energy Eawas 92. 14 kJ · mol-1 calculated by the Kissinger differential method and the Doyle-Ozawa equation. The curing reaction order n 0. 93 was calculated by the Crane empirical equation. The curing characteristics of the coatings,the relationship between the degree of curing and the temperature and the theoretical minimum curing time were analyzed by DSC. It was concluded that the slower the heating rate at the same temperature,the greater the degree of curing of the powder coatings.